Diffusion of Innovations

The diffusion of innovations model describes how change takes place within a social system and provides a schema for the systematic study of the adoption of a product, a practice, or an idea by members of a social system. The most commonly used definition of diffusion of innovations is that articulated by Everett Rogers (1995): ‘Diffusion is the process by which an innovation is communicated through certain channels over time among members of a social system’ (p. 5).

The model offers a logical fit with the traditional task of epidemiology—to systematically study changes in the health of populations with a focus on the patterns of disease occurrence and the factors that influence these patterns. The diffusion model offers opportunities to study and analyze changes in products and exposures as well as in behaviors and policies related to health. The diffusion model and the discipline of epidemiology are both concerned with incidence, prevalence, and change as well as with time, place, and persons. The diffusion model offers a valuable framework to guide epidemiologists in the formulation of research questions to study a wide range of health-related exposures, behaviors, as well as policies and their effects on the health of populations.

The diffusion model is based on two underlying premises: (1) that communication is essential for the diffusion and subsequent acceptance or rejection of an innovation and (2) that new products, practices, and ideas can alter the structure and function of a social system. Change is measured by the numbers of people, groups, or institutions adopting the innovation over time. Consequently, the key variables of interest are time (earliness of knowing about innovation), rate (adoption of different innovations in a social system and/or within and among different social groups), and innovativeness (the degree to which groups or organizations adopt new ideas). Analyses can establish the flow of influence, offer charts of the diffusion curve, develop mathematical models of the diffusion process, and test out contributions of key elements and characteristics.

Lessons learned from diffusion studies in anthropology, sociology, education, folklore, communication, marketing, economics, and public health have helped contemporary scholars and practitioners transform the diffusion of innovation model from a descriptive model into a proscriptive one. Diffusion theory is currently used as an analytic framework for understanding and measuring social change and, in practical application, to guide the design and evaluation of products, programs, and communication strategies in public health and health communication.